Piezoelectric element and process for production thereof

• US 6,610,427 B2
• Filed: 02/07/2002
• Issued: 08/26/2003
• Est. Priority Date: 09/20/2000
• Status: Expired due to Term

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Kitagawa, Mutsumi, Kashiwaya, Toshikatsu
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): XU, LING X
• Application Number:
  US10/072,294
• Publication Number:
  US 20030072972A1
• Time in Patent Office: 565 Days
• Field of Search: 310/328, 310/311, 501/134, 501/135, 501/136, 252/62.9 R, 252/62.9 PZ, 428/688, 428/689, 428/699, 428/701, 428/702
• US Class Current: 428/701
• CPC Class Codes: H10N 30/074 by depositing piezoelectric or electrostrictive layers, e.g. aerosol or screen printing
• CPC Class Codes: H10N 30/097 by sintering
• CPC Class Codes: H10N 30/2047 Membrane type
• CPC Class Codes: H10N 30/50 having a stacked or multilayer structure
• CPC Class Codes: H10N 30/8554 Lead-zirconium titanate [PZT] based

Abstract

A piezoelectric element includes: a ceramic substrate, an electrode and a piezoelectric portion made of a piezoelectric ceramic composition containing a Pb(Mg, Ni)_1/3Nb_2/3O₃—PbZrO₃—PbTiO₃ ternary system solid solution composition being represented by the following general formula (1) as a main component: Pb_x{(Mg_1-yNi_y)_1/3xaNb_2/3}_bTi_cZr_dO₃(1), wherein 0.95≦x≦1.05; 0.05≦y≦0.20; 0.90≦a≦1.10; b,c, and d are decimals falling in a range surrounded by (b, c, d)=(0.550, 0.425, 0.025), (0.550, 0.325, 0.125), (0.375, 0.325, 0.300), (0.100, 0.425, 0.475), (0.100, 0.475, 0.425) and (0.375, 0.425, 0.200) in the coordinates with coordinate axes of said b, c and d, and b+c+d=1.000. The electrode is electrically connected to the piezoelectric portion, and the piezoelectric portion is solidly attached to the ceramic substrate directly or via the electrode.

Claims

1. A piezoelectric element comprising:

a ceramic substrate,

a piezoelectric portion made of a piezoelectric ceramic composition containing a Pb(Mg, Ni)_1/3Nb_2/3O₃—

PbZrO₃—

PbTiO₃ ternary system solid solution composition being represented by the following general formula (1) as a main component, and

an electrode;

wherein said electrode is electrically connected to said piezoelectric portion, and said piezoelectric portion is solidly attached to the ceramic substrate directly or via said electrode;

2. A piezoelectric element according to claim 1, wherein said ternary system solid solution composition has an average particle diameter of 1-10 μ

m with a maximum particle diameter being 5 times as large as the average particle diameter or less.

3. A piezoelectric element according to claim 1, wherein Ni is dispersed in said piezoelectric ceramic composition in such a concentration gradient that the concentration of Ni becomes higher from the interface between said piezoelectric portion and said substrate towards the thickness direction of the piezoelectric portion.

4. A piezoelectric element according to claim 1, wherein Pb in said piezoelectric ceramic composition is replaced by at least one kind of element selected from the group consisting of Sr, Ca and Ba, by 2 to 10 mole % in the whole Pb.

5. A piezoelectric element according to claim 1, wherein Pb in said piezoelectric ceramic composition is replaced by La by 0.2-1.0 mole % in the whole Pb.

6. A piezoelectric element according to claim 1, wherein said piezoelectric portion has a thickness of 1 to 300 μ

m.

7. A piezoelectric element according to claim 1, wherein said substrate has a thickness of 3 μ

m to 1 mm.

8. A piezoelectric element according to claim 1, wherein the ratio of the thickness of the substrate to the thickness of the piezoelectric portion (the thickness of the substrate/the thickness of the piezoelectric portion) is 0.1 to 30.

9. A piezoelectric element according to claim 1, wherein a cross-section of said substrate in the thickness direction has a W-like shape having three inflection points.

10. A piezoelectric element comprising:

a ceramic substrate,

a plurality of piezoelectric portions made of a piezoelectric ceramic composition containing a Pb(Mg, Ni)_1/3Nb_2/3O₃—

PbZrO₃—

PbTiO₃ ternary system solid solution composition represented by the following general formula (1) as a main component, and a plurality of electrodes;

wherein said plurality of piezoelectric portions are laminated with interposing negative electrodes and positive electrodes of said electrodes alternately in each gap between said piezoeleciric portions and a lowermost piezoelectric portion is solidly attached to the ceramic substrate directly or via said electrode;

11. A piezoelectric element according to claim 10, wherein said ternary system solid solution composition has an average particle diameter of 1-10 μ

m with a maximum particle diameter being 5 times as large as the average particle diameter or less.

12. A piezoelectric element according to claim 10, wherein Ni is dispersed in said piezoelectric ceramic composition in such a concentration gradient that the concentration of Ni becomes higher from the interface between said piezoelectric portions and said substrate towards the thickness direction of the piezoelectric portions.

13. A piezoelectric element according to claim 10, wherein Pb in said piezoelectric ceramic composition is replaced by at least one kind of element selected from the group consisting of Sr, Ca and Ba, by 2 to 10 mole % in the whole Pb.

14. A piezoelectric element according to claim 10, wherein Pb in said piezoelectric ceramic composition is replaced by La by 0.2-1.0 mole % in the whole Pb.

15. A piezoelectric element according to claim 10, wherein said piezoelectric portions have a thickness of 1 to 300 μ

m.

16. A piezoelectric element according to claim 10, wherein said substrate has a thickness of 3 μ

m to 1 mm.

17. A piezoelectric element according to claim 10, wherein the ratio of the thickness of the substrate to the thickness of the piezoelectric portions (the thickness of the substrate/the thickness of the piezoelectric portions) is 0.1 to 30.

18. A piezoelectric element according to claim 10, wherein a cross-section of said substrate in the thickness direction has a W-like shape having three inflection points.

19. A piezoelectric element comprising:

a ceramic substrate,

a piezoelectric portion made of a piezoelectric ceramic composition containing a Pb(Mg, Ni)_1/3Nb_2/3O₃—

PbZrO₃—

PbTiO₃ ternary system solid solution composition represented by the following general formula (1) as a main component, and said piezoelectric ceramic composition contain particles having NiO as a main component on the surface and/or in the interior thereof, and

an electrode;

wherein said electrode is electrically connected to said piezoelectric portion, and said piezoelectric portion is solidly attached to the ceramic substrate directly or via said electrode;

20. A piezoelectric element according to claim 19, wherein said ternary system solid solution composition has an average particle diameter of 1-10 μ

m with a maximum particle diameter being 5 times as large as the average particle diameter or less.

21. A piezoelectric clement according to claim 19, wherein said particles having NiO as a main component contain a solid solution of NiO and MgO.

22. A piezoelectric element according to claim 19, wherein Ni is dispersed in said piezoelectric ceramic composition in such a concentration gradient that the concentration of Ni becomes higher from the interface between said piezoelectric portion and said substrate towards the thickness direction of the piezoelectric portion.

23. A piezoelectric element according to claim 19, wherein Pb in said piezoelectric ceramic composition is replaced by at least one kind of element selected from the group consisting of Sr, Ca and Ba, by 2 to 10 mole % in the whole Pb.

24. A piezoelectric element according to claim 19, wherein Pb in said piezoelectric ceramic composition is replaced by La by 0.2-1.0 mole % in the whole Pb.

25. A piezoelectric element according to claim 19, wherein said piezoelectric portion has a thickness of 1 to 300 μ

m.

26. A piezoelectric element according to claim 19, wherein said substrate has a thickness of 3 μ

m to 1 mm.

27. A piezoelectric element according to claim 19, wherein the ratio of the thickness of the substrate to the thickness of the piezoelectric portion (the thickness of the substrate/the thickness of the piezoelectric portion) is 0.1 to 30.

28. A piezoelectric element according to claim 19, wherein a cross-section of said substrate in the thickness direction has a W-like shape having three inflection points.